1. Field of the Invention
The present invention relates to an improved small size low loss ballast system for starting and operating high voltage discharge lamps using commonly supplied 120 volt power sources.
2. Discussion of the Background
The prior art contains many examples of starting circuits for gaseous discharge lamps or electric discharge lamps. Most of these circuits provide a ballast circuit involving a transformer in series with the load. The prior art circuitry vary depending upon the exact nature of the electric discharge lamp, i.e., fluorescent, metal halide, high pressure sodium vapor lamp (HPS) etc. With improvements in the construction of the gaseous discharge lights themselves, have come associated problems with providing ballast circuitry. These problems result from the development of efficient high voltage discharges which must have a small size, low loss ballast and yet be able to be operated from 120 volt power sources.
One prior art solution enabling the use of 120 volt power source was the low wattage HPS (high pressure sodium) lamps which have a requirement for an operating voltage of around 55 volts so that a 120 volt reactor ballast can be used plus an electronic ignitor. However, these HPS lamps require higher amperage because HPS lamps require high volt-amps for a given lamp wattage. That is for example, a 50 watt HPS has a requirement for 52 Vx 1.18A=61.4 VA. The higher amperage causes higher losses and thus a larger size device needs to be constructed.
The current trend in electric discharge lamps is to produce systems which have total higher efficiency and which produce "white light". With this higher efficiency comes the requirement for a higher operating voltage and when voltage step up is required in addition to ballasting, the physical size of the structure becomes a problem and the losses become excessive because of the requisite high temperatures. These high temperatures particularly effect the use of plastic fixtures in the devices for the lamp.